An automotive closure, such as a door for an automobile passenger compartment, is hinged to swing between open and closed positions and conventionally includes a door latch that is housed between inner and outer panels of the door. The door latch functions in a well known manner to latch the door when it is closed and to lock the door in the closed position or to unlock and unlatch the door so that the door can be opened manually.
The door latch is operated remotely from the exterior of the automobile by two distinct operators--typically a key cylinder that controls the lock mechanism and an outside door handle or push button that controls the release mechanism.
The door latch is also operated remotely from inside the passenger compartment by two distinct operators--a sill button that controls the lock mechanism and an inside door handle that controls the release mechanism. Vehicle door latches for upscale automobiles may also include power door locks in which the lock mechanism is motor driven and/or a keyless entry in which a key fob transmitter sends a signal to a receiver in the vehicle to operate a motor driven lock mechanism.
See for instance, U.S. Pat. No. 5,277,461 granted to Thomas A. Dzurko et al Jan. 11, 1997 for a vehicle door latch, which is hereby incorporated in this patent specification by reference, discloses a typical door latch of the above noted type. The door latch disclosed in the Dzurko '461 patent includes an unlatching lever that is pivotally mounted on a stud that is secured to a metal back plate and a metal face plate at opposite ends. Unlatching lever is operated to unlatch the vehicle door by an inside handle lever that is connected by a suitable linkage for rotation by an inside door handle (not shown). Unlatching lever is also operated by an outside handle lever that is connected by suitable linkage for rotation by an outside door handle (not shown).
The Dzurko door latch also includes a locking lever that is pivotally mounted on the stud. Locking lever is operated by an inside locking lever that is pivotally mounted on the flange of the metal face plate near the inside handle lever. The inside locking lever is operated by an inside sill button or lock slide through a suitable linkage (not shown). Locking lever is also operated by an outside locking lever that is operated by a key lock cylinder through a suitable linkage (not shown). In some instances, for example in upscale automobiles, locking lever is also power operated by a remotely controlled linear electric motor or the like in a well known manner (not shown).
The door latch disclosed in the Dzurko '461 patent is unlocked and unlatched in the following sequence. First the locking lever is moved to the unlocked position by the inside locking lever, the outside locking lever, or in the instance of a vehicle equipped with power door locks, a remotely controlled motor. This moves the intermittent lever to the unlocked position. After the door latch is unlocked, the door latch is unlatched by moving the unlatching lever via inside handle lever or outside handle lever to the unlatched position pulling intermittent lever and detent down to unlatch the door lock. The vehicle door then may be pushed or pulled open manually.
U.S. Pat. No. 5,328,219 granted to Jeffrey L. Kochan et al Jul. 12, 1994 shows a vehicle closure latch of the same general type. Door latches of the type disclosed in the Dzurko '461 patent have been used successfully by General Motors for many years.
The purpose of the locking function, of course, is to prevent unauthorized entry into the automotive vehicle by locking the vehicle doors. However, unauthorized persons can enter locked automotive vehicles by gaining access to the sill button, electric switch or other operator inside the vehicle that controls the locking function of the door latch.
Thus there is a desire not only to make further improvements in the door latches of the above noted type but also to make further improvements that also prevent unauthorized entry.